Gulf of Maine Seasonal Sea Surface Temperature Update

Seasonal Patterns in Sea Surface Temperatures

Author

Adam Kemberling

Published

December 1, 2022

About the Updates:

Over the past decade, scientists at the Gulf of Maine Research Institute have led a body of research that highlights the rapid pace of warming in the Gulf of Maine. To keep you informed, we share seasonal updates about conditions in the Gulf of Maine.

Note About the Data: The figures in this report are created using remotely-sensed satellite data as part of publicly funded research efforts. Satellite SST data was obtained from NOAA’s National Center for Environmental Information (NCEI), with all maps and figures displaying NOAA’s Optimum Interpolation Sea Surface Temperature Data.

Note on Preliminary Data: This dataset has a 2-week latency period, during which values may change due to quality control measures. Any data within 14 days of the publishing date may be subject to change.

The Gulf of Maine Region

For analyses like these, it is important to be clear about the spatial extent that “defines” the Gulf of Maine (Figure 1), as different borders could produce different results. The spatial domain we use as the “Gulf of Maine” is displayed below. This area is consistent with previous reports and publications GMRI has produced.

An overhead view of the Gulf of Maine region. Landmasses and political boundaries for the United States and Canada are displayed. A blue dotted line outlining a box with a transparent blue fill is shown to demark where satellite data for the analysis has been used.

For this seasonal report, we present an analysis of SST for Fall (September 1st - November 30th).

Highlights

The average SST for the Gulf of Maine during the fall (September 1st - November 30th) of 2022 was 60.14°F, making it the 2nd hottest fall on record for the period of 1982-2022 — the period over which the satellite data used are available. These temperatures are 4.46°F above the long-term (1982-2011) Fall average of 55.69°F.

Weekly Temperatures

In the below table, we highlight how the SST for each week this fall compares to a 30-year baseline period (climatological averages from 1982 through 2011).

The observed SST, long-term average SST, and SST anomalies (departures from the long-term average SST) are shown. As expected, SSTs generally rise as the summer season progresses, with anomalies showing no clear trend over the course of the season. Rather, departures from the long-term average hovered around 3°F above normal with a few weeks punctuated by anomalies exceeded 5°F.

Observed, climatological average, and deviation from the climatological average (i.e., temperature anomaly) for SST at a weekly resolution in the Gulf of Maine during summer 2022 (defined as June 1st - August 31st)
Weekly Sea Surface Temperatures - Fall
Fall (September 1st - November 30th)
One-Week Period Observed Temperature Climatological Average Temperature Anomaly
°F °C °F °C °F °C
Sep 01 - Sep 03 66.7 19.3 61.6 16.40 5.15 2.86
Sep 04 - Sep 10 66.3 19.1 61.1 16.20 5.22 2.90
Sep 11 - Sep 17 65.4 18.5 60.4 15.80 5.00 2.78
Sep 18 - Sep 24 63.2 17.3 59.6 15.30 3.60 2.00
Sep 25 - Oct 01 60.7 16.0 58.6 14.80 2.13 1.19
Oct 02 - Oct 08 59.7 15.4 57.5 14.20 2.17 1.21
Oct 09 - Oct 15 59.4 15.2 56.4 13.50 3.06 1.70
Oct 16 - Oct 22 59.4 15.2 55.2 12.90 4.22 2.34
Oct 23 - Oct 29 59.6 15.3 54.0 12.20 5.58 3.10
Oct 30 - Nov 05 59.5 15.3 52.9 11.60 6.56 3.64
Nov 06 - Nov 12 58.5 14.7 51.9 11.10 6.62 3.68
Nov 13 - Nov 19 56.7 13.7 50.9 10.50 5.82 3.23
Nov 20 - Nov 26 53.9 12.2 49.9 9.96 3.95 2.20
Nov 27 - Nov 29 51.9 11.0 49.2 9.57 2.66 1.48
Data Source: NOAA OISSTv2 Daily Sea Surface Temperature Data.
Climatology Reference Period: 1982-2011.

Monthly Statistics

Looking at monthly averages (as opposed to week-by-week conditions), we see each month was 3.88°F or more above the 1982-2011 climatological average. November showed the largest deviation from the long-term climatological average, with an average SST anomaly of 5.38°F.

Month Observed Temperature Climatological Average Temperature Anomaly Temperature Progression
°F °C °F °C °F °C temp_list
Sep 64.3 17.9 60.1 15.6 4.16 2.31
Oct 59.6 15.3 55.7 13.2 3.88 2.15
Nov 56.4 13.6 51.1 10.6 5.38 2.99
Data Source: NOAA OISSTv2 Daily Sea Surface Temperature Data.
Climatology Reference Period: 1982-2011.

How Does 2022 Compare?

2022 is among the warmest falls seen in the Gulf of Maine during this 41 year period. When compared against all previous falls for which we have reliable satellite data (i.e., back to 1982), this year ranks 2nd among the hottest on record. The top 5 warmest Fall have all occurred in the last decade.

Marine Heatwave Timeline

The most commonly used definition of a “marine heatwave” (MHW) is when daily average SST’s exceed the 90th percentile of a climatological (i.e., 30-year) average for at least 5 consecutive days. Successive heatwave gaps of 2 days or less are considered part of the same event.

Using this broadly accepted definition, the Gulf of Maine has experienced MHW conditions for 0.97 of fall 2022 A brief reprieve in mid-May lasted less than two days, so it did not constitute a break in the heatwave event.

Heatwave Anomaly Timeline

Presenting SST conditions in terms of anomalies (figure below) as opposed to absolute values (figure above) illustrates in greater detail the magnitude of MHW conditions throughout the fall.

The most extreme anomalies this fall occurred in August, with temperatures exceeding \(6°\)F above the climatological average.

Heatmap of Temperature Anomalies and Heatwave Events

Looking at the full record of daily SST anomalies in the Gulf of Maine (figure below), the distinct thermal regime shift beginning around 2010 is evident. Indeed, since 2012, the Gulf of Maine has experienced far more persistent MHW conditions (indicated by solid black lines) than at any other point in the satellite record.

Monthly Rankings Heatmap

Longest Heatwave on Record

This summer marked the conclusion of the Gulf of Maine’s longest heatwave event.

This event spanned from 2021-01-01 to 2022-06-19 - ultimately lasting 535 days. During that period temperatures were on average 3.87°F above temperatures observed during the 1982-2011 climate reference period.

Spatial Distribution of Seasonal Anomalies

From a spatial perspective, the Gulf of Maine and surrounding areas experienced above average SST’s for much of the region during fall 2022, but with particularly warm patches to the south and east of Georges Bank. The highest seasonally averaged anomaly of any location above was 8.73°F.

Monthly Temperature Anomalies

Average monthly temperature anomalies are displayed below. The warmest anomalies were concentrated just south of the domain studied in this analysis in June, by July SST anomalies within the Gulf of Maine were equally hot. Monthly-averaged SST anomalies in the Gulf of Maine and the surrounding areas reached > 8°F warmer than during our climate reference period (1982-2011).

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A work by Adam A. Kemberling

Akemberling@gmri.org

 

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